Look at the code for the first image. The location, or 'path', of the image is different to those on the index.html page.

My photo of Seaford Pier

The externally linked image is exactly the same, though. That's because the URL of the Wikimedia image hasn't changed.

Photo of Seaford Beach, Victoria. Creative Commons license https://commons.wikimedia.org/wiki/File:Seaford_Beach_1.jpg